Short-Lived K 2 S Molecules in Superionic Potassium Sulfide

摘要: First principles molecular dynamics study enables us to elucidate the formation of short-lived K2S molecules in superionic potassium sulfide. Covalent electron densities exist between ionized immobile sulfurs and their coordinated mobile potassiums forming respective covalent Coulomb bonds them. Both induce indirect attractions di-interstitial on mid-sulfurs molecules. The lifetime is 120 fs at 1050 K. density also exists pairs with 110 fs. three constrain self-diffusion sulfide which reduces Haven’s ratios potassiums. absence rigid dimers indicates a failure chain models for diffusion. reduce them comparing completely states induces melting sublattic...